Lake warden Dafydd Bowen's grey "crocodile" at Llyn Tegid (Bala Lake)

Llyn Tegid, also called Bala Lake, lies in Gwynedd, Wales. It is about 3.7 miles long, half a mile wide and up to 42 metres deep. Its waters hold a genuine rarity, the gwyniad, a whitefish found only here. In 1909 Marie Trevelyan wrote that "a dragon was coiled up at the bottom of the lake". Welsh tradition tells of the afanc, a water monster, and of the drowned town of Tegid Foel.

About 1975. The lake warden was at work. Sources spell the name three ways, Dowie, Dafydd and Dewi Bowen. "I looked out of my office window and saw this thing moving through the water 200 yards away," Bowen recalled. "It was grey, about eight feet long and looked like a crocodile with a small hump in the middle."

Another version of the account adds detail. The thing was "at least 8ft long". Its front and rear ends sat about four inches above the water. It was coming towards the shore. It disappeared before Bowen reached the shore.

There was one witness. No photograph, no film, no trace. Yet the report is remembered as the first recorded modern sighting of Teggie, and others followed. In 1979 the Sunday Express carried Anne Jones's report of a "huge hump-backed beast". In March 1995 Paul and Andrew Delaney said that something in the water "straightened up and towered 10 feet in the air."

That August, Fortean Times No. 82 told the warden's story. Bowen was 72 by then, a teetotaller with 25 years on the lake. The account returned in The Independent in 2002, in North Wales Live in 2016 and in Herald.Wales in 2021. A Dewi Bowen is listed among the contributors to Celtic Monsters, an S4C and BBC series, in 2007. It is likely the same person.

No official investigation of the sighting is recorded. In the 1990s a Japanese television crew spent three days searching the lake with divers and a small submarine. Accounts of the result differ.

One says they found nothing. Another says they went home with old welly boots and murky footage. Others claim a sonar trace of a large unidentified object. In 1995 Dr Rick Leah of Liverpool University hoped to search with "£10,000 digital echo sounder equipment" if funding could be found.

Arwel Morris, who followed Bowen and became the Snowdonia National Park warden at the lake, has said that "Most disturbances on the lake can be easily explained". He points to a shoal of fish, trapped gas bubbling to the surface, or an otter with her young looking like humps. Others suggest a large pike. Local lore speaks of seals escaped from wartime military experiments, though nothing documents it. Andy McGrath, author of Beasts of Britain, suggests amphibious animals moving between waters.

The warden's low grey crocodile does not match the Delaneys' tall, long-necked animal, a puzzle later writers have noted. Teggie has since featured in The Unexplainers on BBC Two Wales in 2019 and in an independent film, Teggie: The Legend of the Lake. The first modern sighting remains what it was in 1975. One warden at one window. One grey shape heading for the shore.